B_{s,d} -> l+ l- in the Standard Model with Reduced Theoretical Uncertainty

Abstract

We combine our new results for the O(αem) and O(α 2 s ) corrections to B s,d → ℓ + ℓ − , and present updated branching ratio predictions for these decays in the standard model. Inclusion of the new corrections removes major theoretical uncertainties of perturbative origin that have just begun to dominate over the parametric ones. For the recently observed muonic decay of the Bs meson, our calculation gives B(Bs → µ + µ − ) = (3.65 ± 0.23) × 10 −9 .

Closing the window on single leptoquark solutions to the B-physics anomalies

“…In this fit we used R exp K ( * ) , 8,9 and the theoretically clean B(B s → µµ) exp = 3.0 ± 0.6 +0.3 −0.2 × 10 −9 . 14,15 The possibility of having…”

Distribution Amplitudes of Heavy Hadrons: Theory and Applications

“…From one side, the remarkable operation of the hadron collider LHC at CERN provides us with a lot of interesting and exciting results and, from the other side, many more results can be obtained from the B-factory at KEK which is under construction now and hopefully to be run in a year from now. Among the excellent achievements obtained at the LHC, there is the measurement of the rare purely leptonic decay B s → µ + µ − by the LHCb and CMS collaborations [1] in a nice agreement with the theoretical expectations based on the Standard Model (SM) (see, for example, [2] and reference therein) and the evidence of the similar decay B 0 → µ + µ − seen by the same collaborations [1] is also in agreement with the SM predictions [2]. Let us note that both decays were considered as a clean candle into possible new physics at the flavor-physics frontue, when predicted branching fractions are substantially larger the SM expectations.…”

Rare semileptonic B→K(π)li−lj+ decay in a vector leptoquark model

“…Now comparing the theoretical [29] branching ratios of B q → µ + µ − processes with the 1σ range of experimental values [30], the constraint on r and φ N P is computed for scalar LQ model in our previous work [11,18]. If we assume that both the scalar and vector LQs have same order mass, M LQ = 1 TeV, one can use the same constraint on r and φ N P parameters to study the processes mediated via vector LQ.…”

“…Similarly using the theoretical predictions [29] and the experimental upper limits [31,32] on B q → e + e − (τ + τ − ) processes, the constraint on the product of scalar LQ couplings are presented in Table I, which are found to be rather loose as the measured branching ratios of B d,s → τ + τ − (e + e + ) are not very precise.…”